A manual of bacteriology, clinical and applied / by Richard T. Hewlett.

  • Hewlett, R. Tanner (Richard Tanner), 1865-1940.
Date:
1902
Catalogue details

Licence: Public Domain Mark

Credit: A manual of bacteriology, clinical and applied / by Richard T. Hewlett. Source: Wellcome Collection.

    129/626 (page 113)
    Blood may be obtained from a patient for the aggluti¬ nation reaction, for microscopical examination, or for culture experiments, by pricking the finger or the lobe of the ear with a sterile needle or lancet, or with half a steel pen (nib) ; the skin having been first disinfected by washing with soap and water, then with 1-^20 carbolic solution, and finally, to remove the antiseptic, with absolute alcohol followed by ether. Organisms, in natural infections in man, are usually present only in small numbers in the blood, and for demon- strating them by culture methods it is necessary to withdraw 2-5 c.c. from a superficial vein by means of a sterile syringe with antiseptic precautions, and to sow this on agar plates. Although the modern methods of isolation and cultiva¬ tion have rendered immense service to bacteriology, they have also had the effect of diminishing the attention paid to the exact morphology and biology of organisms. At the present time there is a tendency to investigate bacteria en masse rather than to study them as individual living forms, and the following remarks by Marshall Ward 1 may be aptly quoted in this connection : ‘We must remember that Be Bary and Brefeld had aimed at obtaining a single spore isolated under the microscope, and tracing its behaviour from germination continuously to the production of spores again; and when we learn how serious were the errors into which the earlier investigators of the mould fungi and yeasts fell, owing to their failure to trace the development continuously, from spore to spore, and the triumphs obtained afterwards by the methods of pure cultures, it is not difficult to see how inconclusive and dangerous all inferences as to the morpho¬ logy of such minute organisms as bacteria must be unless the plant has been so observed. As a matter of fact, the 1 Address in Botany, Brit. Assoc. 1897. Nature 56, 1897, p. 455 et seq. I